Modification of aluminum current collectors with a conductive polymer for application in lithium batteries

Abstract

Although often overlooked, current collectors play a significant role in the performance, safety, and stability of lithium batteries. Here we present a strategy to modify conventional Al current collectors using a conducting polymer, significantly decreasing contact resistance and improving battery performance. The oxidant Fe (III) p-toluenesulfonate is aerosolized onto an aluminum foil current collector, followed by polymerization of 3, 4-ethylenedioxythiophene (EDOT) by chemical vapor deposition (CVD). As such, this fabrication technique should scalable using roll-to-roll or similar fabrication methods. The coated foil was used as a cathode current collector in lithium batteries. The improvement of the current collector is determined by electrochemical test in coin cells with C-LiFePO4 (C-LFP) and lithium as active materials. At 15C discharge rate, the new composite C-LFP-PEDOT-Al electrode provides a ~30% increase in discharge capacity compared to the standard C-LFP-Al electrode. The new composite has a perfect stability over 50 cycles at a C/2.5 rate. Keywords: Poly (3, 4-ethylenedioxythiophene), C-LiFePO4, Current collector coating, Chemical vapor deposition, Lithium ion batteries